Lubricating oil



Patented Feb. 24, 1948 UNITED STAT LUBRICATING OIL No Drawing. Application July 20, 1945, Serial No. 606,286

6 Claims. 1

The. present invention is directed to an improved lubricating composition. More specifically, the present invention is directed to a composition adapted for use as a lubricating oil in internal combustion engines subjected to extreme cold.

In order to allow an internal combustion engine to be readily started when cold it is necessary that the lubricating oil employed in the motor have a pour point and viscosity at the starting temperature which permits the starter to turn the motor at the proper rate and which allows sufficient oil to be pumped through the engine to produce adequate lubrication. When internal combustion engines are operated in extremely cold climates, it is difiicult to obtain an oil having satisfactory viscosity characteristics under normal operation conditions and having a sufiiciently low pour point and viscosity at starting temperatures to allow the motor to be readily started. It has now become conventional to provide some internal combustion motors, such as the engines of aircraft which are to be operated under low temperature conditions, with means for diluting a portion of the lubricant with naphtha at the time the motor is stopped so that the lubricant supplied in the engine will have a sufficiently low viscosity to permit starting the motor after it has been chilled to the prevailing atmospheric temperatures. The armed forces of the United States at present specify the temperature of -65 F. as a maximum pour point, by method ASTM designation D9'7-39, for aviation grade lubricating oil diluted with a 30 per cent naphtha for lubricating oils approved for use in cold climates. Aviation grade lubricating oils which have to meet this requirement usually have a viscosity within the range of 80 to 100 viscosity Saybolt seconds universal at 210 F. and are usually prepared by blending a dewaxed bright stock with a dewaxed light distillate lubricating oil fraction. Difficulty has heretofore been encountered in producing aviation grade lubricating oils, particularly the heavier oils having a 100 viscosity, S. S. U., at 210 F. which have a satisfactorily low diluted pour point even though a conventional pour depressant, such as the product obtained by condensing a chlorinated paraflin wax with naphthalene as described in U. S. Patent 1,815,022, is added to the petroleum oil blend.

It is an object of the present invention to produce a lubricating composition capable of flowing at very low temperatures. More specifically, it is an object of the present invention to produce a composition suitable for lubricating internal combustion engines under normal operating conditions and which, when diluted with naphtha, has a poor point no higher than 65 F.

In accordance with the present invention, an improved lubricating composition suitable for use in internal combustion engines is obtained by admixing fractions in the lubricating oil range separated from paraifin base crude petroleum and substantially free from parafiin wax with a minor portion of wax separated from a naphthenic base crude petroleum and a minor portion of product obtained by condensing chlorinated paraffin wax with an aromatic hydrocarbon.

Parafiin base petroleum fractions in the lubricating oil range which are suitable for forming the major portion of an aviation grade lubricating oil are most conveniently obtained by separately dewaxing bright stock obtained from a paramn base oil and wax-distillate obtained from a paraffin base oil and blending the dewaxed fractions to obtain a mixture having a viscosity within the range of to S. S. U. at 210 F. and a pour point of the order of 15 F. While this is in general the most satisfactory method for preparing the lubricating oil employed as the major portion of the improved lubricant of the present invention, it will be understood that other methods may be followed to obtain such materials. For example, if desired, several fractions of different viscosities but containing wax may be blended and the blended material dewaxed to produce the blended lubricating oil mixture having a pour point of the order of 15 F. As another alternative, a single fraction separated from a paraflin base crude oil and having proper viscosity characteristics may be dewaxed to obtain a product having the desired pour point. However, in most cases, it will be commercially desirable to obtain the lubricating oil portion of the-lubricant by blending a dewaxed bright stock and dewaxed wax-distillate fraction.

To the lubricating oil fraction is added a wax fraction separated from a naphthenic base petroleum and a product obtained by condensing a chlorinated paraflin wax with an aromatic hydrocarbon. The separation of a wax fraction from a lubricating oil is well known to the art and, accordingly, any of the well known methods for separating the wax from the naphthenic base oil may be employed to obtain this material. It may be stated that if desired a crude wax separated from a naphthenic base petroleum and including a substantial amount of naphthenic oil in admixture with the Wax may be employed, if desired. It will be understood that the inclusion of excessive amounts of naphthenic base oil in the paraffinic base oil will cause a deterioration in the quality of the finished product and usually the amount of naphthenic base oil present in the crude wax should not be greater than the amount of the wax, although greater amounts of naphthenic base oil, for example, twice the amount of wax derived from the naphthenic base oil, may be used without unduly reducing the quality of the finished product.

The condensation of chlorinated paraffin wax with an aromatic hydrocarbon to obtain a condensed hydrocarbon product is well known to the art. A method for producing such products by chlorinating a parafin wax and subsequently condensing the chlorinated wax with an aromatic hydrocarbon, such as benzene or naphthalene is described in U. S. Patents 1,815,022 and 2 015,748. The preparation of such products in itself forms no part of the present invention and, accordingly, its reaction will not be described in any greater detail.

The amount of wax derived from a naphthenic base petroleum and the amount of product obtained by condensing a paraffin wax with an arcmatic hydrocarbon used in the present invention may be varied over a substantial range and satisfactory results obtained. For example, the wax derived from a naphthenic base petroleum may be used in an amount within the range of .1 to 1% and preferably within the range of .2 to .4% of the lubricating oil derived from a paraffinic base petroleum. In like manner, the condensation product obtained by condensing a chlorinated paraffin wax with an aromatic hydrocarbon may be used in an amount within the range of .2 to 2% and preferably within the range of .4 to .8% of the lubricating oil derived from a parafiinic base petroleum. It is desirable to employ twice as much condensation product as wax derived from a naphthenic base petroleum.

The practice of the present invention will be further illustrated by the following example:

EXAMPLE A dewaxed parafiin base bright stock and a dewaxed paraffin base distillate were blended to produce a blend having a viscosity of 100 S. S. U. at 210 F. and a pour point of 10 F. This oil was separated into six difierent samples, each sample was separately treated and the results of the treatment given in columns 1 to 6 in the table below. The sample in column 1 was diluted with 30% of naphtha (consisting of 80% specification AN-N-3 naphtha and 20% commercial Xylene) and the pour point of the diluted material obtained as the diluted pour point listed in the table. The sample in column 2 had added thereto a commercial pour depressant obtained by condensing chlorinated parafiin wax with aromatic hydrocarbons and known as Parafiow. The third sample shows the results of admixing with the blended lubricating oil a wax obtained from a naphthenic base petroleum. Columns 4, 5 and 6 show the results of the blended lubricating oil having both the condensed parafiin wax and aromatic hydrocarbon pour depressant and wax from naphthenic base petroleum added thereto in varying amounts.

Table GolumnNo ..-1\2l3145 6 It will be seen that the oil in columns 1, 2 and 3 did not have a diluted pour point of 65 F. as required by specifications for aviation grade lubricating oils whereas the blends of columns 4, 5 and 6 were entirely satisfactory.

While I have given specific examples illustrating the practice of the present invention, it is to be understood that these examples were given only by way of illustration and are not intended to limit the invention. For example, the viscosity and initial pour point of the lubricating oil fractions used as the principal constituent of the blend may be varied over a substantial range. In like manner, the amount of wax separated from a naphthenic base petroleum and the amount of pour depressant obtained by condensing a paraffin wax with an aromatic hydrocarbon may be varied over a substantial range.

Having fully described and illustrated the present invention, what I desire to claim as new and useful and to secure by Letters Patent is:

1. An improved lubricating oil comprising a major portion of substantially wax-free oil in the lubricating oil range separated from a paraiiin base crude petroleum, a minor portion of wax separated from a naphthenic base crude petroleum and a minor portion of the condensa-- tion product formed by condensing chlorinated paraffin wax with an aromatic hydrocarbon.

2. An improved lubricant comprising a major portion of substantially wax-free oil in the lubricating oil range derived from a parafiin base crude petroleum, a minor portion of wax separated from a naphthenic base crude petroleum, a minor portion of the condensation product formed by condensing chlorinated parafdn wax with an aromatic hydrocarbon and a substantial portion of naphtha.

3. An improved lubricant in accordance with claim 2 in which substantially twice as much condensation product as wax derived from a naphthenic base petroleum is present in the lubricant.

4. A lubricant in accordance with claim 2- in which the wax derived from a naphthenic base crude is present in an amount within the range of .2 to .4 per cent by volume of the substantially wax-free oil.

5. A lubricant in accordance with claim 2 in which th condensation product is present in an amount within the range of .4 to .8 per cent by volume of the substantially wax-free oil.

6. A lubricant in accordance with claim 2 in which the wax derived from a naphthenic base crude is present in an amount within the range of .2 to .4 per cent and in which the product condensation is present in an amount within the range of .4 to .8 per cent by volume of the substantially wax-free oil.

DONALD B. GILLETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,209,165 Martin et a1 July 23, 1940 2,352,213 Lieber et al. June 2'7, 1944 

